The Tritone Substitution (2)
Updated: Sep 7, 2021
In the previous blog I stated the proposition,
The more you alter a Dominant chord the more like its Tritone it becomes.
I gave a technical definition:
A Tritone Substitution is the substitution of one Dominant 7th chord (possibly altered or extended) with another (possibly altered or extended) that is three whole-steps (a tritone) from the original chord. It's also known as a Flat-5 Substitution, since a tritone is a flatted 5th (technically speaking, a Diminished 5th) from the original root.
Then I demonstrated validity of the proposition by altering a Bb9 chord until it looked like an unaltered E9.
Next I applied Tritone Subs to a Dominant Cycle, namely, the Bridge to any Rhythm Changes tune.
I also applied Tritone Subs to a 12-Bar Blues form.
All of which leads us to the current lesson: Tritone Substitution, Part 2:
The Tritone Substitution concept can be applied to any chord progression that moves cyclically, that is, a cycle of 4ths.
If you don't know what I mean by, "cyclically," stop right here and download the 5-Lesson Foundational Series. This series of lessons teaches the Circle of Keys as an organizational mechanism by which you ensure that whatever you learn is drilled in every key in all possible positions. It also gives you a method to find any note, anywhere, without memorizing note names on every string. That is a beautiful thing! Since cycles are one of the main ways chords move in music, you really should get a handle on it! This lesson series gives you just that.
You can download the 5-Lesson Foundational Series right here for free with no further obligation or commitment:
The first section of Autumn Leaves would be a good example of a chord progression that moves cyclically and therefore is a candidate for the use of Tritone Substitutions.
Here’s the same section with the Tritone Subs:
Note: in the 4th bar, the Tritone of C cannot be used because the root of the next chord in the tune is the Tritone of C. So we use C6 instead to maintain the feeling of a chord change every two beats.
Also, remember that even though the chart is written in terms of 7th chords, extensions and alterations can be applied at will, depending on what you want to hear.
In my opinion, Autumn Leaves illustrates that the technical definition of a Tritone Substitution is too narrow. The chord from which the Tritone Sub derives doesn’t have to be Dominant. However, the Tritone Sub is always Dominant, so the term, “Tritone Dominant Substitution” still works.
All the Things You Are
Another song that illustrates the above is All the Things You Are. Here’s the entire form of the tune:
Here’s the tune with the Tritone Subs. Because of the length of the form, I'm going to break it up into sections. Here's the A1 section:
Note: 1st bar of 2nd line - we can't use the Tritone Sub of Db because the next chord of the tune (G7) is the Tritone Sub of Db.
Here's the A2 section. It's exactly the same as A1 transposed a 4th down:
Note: 5th bar; same situation as the previous section. We can't use the Tritone Sub of Ab (D) because the next chord in the tune is the Tritone Sub.
Now for the Bridge:
Note: We can't use the Tritone Sub of G in the 4th bar because it doesn't lead well into the next chord (F#-7).
Same for the Emaj7; the Tritone Sub does not lead well into the C7+ (i.e. it's not a cyclical progression).
Now for the last section:
Note: Tritone Subs don't work for the middle line because it's a chromatic progression which is about as far as you can get from a cycle of 4ths. The cycle of 4ths is where the Tritone Sub works the best.
So that’s how Tritone Subs can be used in any kind of cyclical progression.
In the next lesson, I’ll talk about what guitar players should actually play when there’s a bass player in the mix.
Preview: Omitting the root and just playing the upper voices gives the bass player the freedom to use Tritones in his lines.
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